The preparation of mercaptoalcohols by the reaction of epoxides with hydrogen sulphide is known. Thus, the production of mercaptoethanol by the action of H.sub.2 S on ethylene epoxide, or ethylene oxide, has already formed the subject of a certain number of investigations. However, such processes are unsuitable when mercaptoalcohols containing more than 3 carbon atoms are to be prepared.
To this end, Belgian Pat. No. 731,879 proposes the production of mercaptoalcohols from epoxides containing more than 3 carbon atoms. Production is based on the use of strongly basic catalysts such as alkali metal hydroxides, alcoholates and phenolates, and tertiary and/or quaternary onium bases. Belgian Pat. No. 731,881 uses various amines, and U.S. Pat. No. 3,394,192 uses trialkylamines, as other basic catalysts. U.S. Pat. No. 3,462,496 relies on catalysts of the same type: alkali metal or alkaline-earth metal hydroxides, trialkylamines, quaternary ammonium hydroxides or else chromium salts of fatty acids.
More recently, Japanese Patent Application No. 8059160 recommends the addition of carbon disulphide and of alcohols to the reaction of an epoxide with alkali metal hydrogensulphides. Furthermore, U.S. Pat. No. 4,281,202 proposes the use of zeolites in the potassium or sodium form as catalysts. French Pat. No. 2,480,281 describes catalysts consisting of anionic exchange resins, which have previously been the subject of French Pat. No. 1,359,678.
However, particularly for production of mercaptoalcohols containing more than 3 carbon atoms, all these catalysts require relatively long reaction times to finish with a degree of conversion of the epoxide and/or a yield of the desired product which are mediocre or inadequate. Furthermore, the majority of the processes of the prior art take place in the presence of solvents or other additives, even when the reaction mixture remains in the liquid state during the reaction.